Fraction Calculator
Add, subtract, multiply & divide fractions
Reduce a fraction (or mixed number) to its lowest terms.
Convert to a fraction
How to Use
- 1Pick a mode: calculate, simplify or decimal → fraction.
- 2Type the numerator and denominator (add a whole number for mixed).
- 3Choose +, −, × or ÷ for a two-fraction calculation.
- 4Read the simplified fraction, mixed number and decimal instantly.
Fraction Rules
- Add / Subtract a/b ± c/d = (a·d ± c·b) / (b·d)
- Multiply a/b × c/d = (a·c) / (b·d)
- Divide a/b ÷ c/d = (a·d) / (b·c)
- Simplify divide both by GCD(a, b)
Quick Examples
Tap an example to load it above.
Everything about the Fraction Calculator
A quick, practical guide to adding, subtracting, multiplying and dividing fractions.
A fraction represents a part of a whole and is written as one number over another, with a numerator on top and a denominator on the bottom. This fraction calculator adds, subtracts, multiplies and divides fractions and mixed numbers, reduces any result to its lowest terms, and also shows the answer as a decimal.
Fractions turn up constantly: in cooking measurements, construction, money, time and every maths class. The tricky part is usually finding a common denominator and then simplifying, so this tool handles both steps for you and shows the answer the moment you type.
Tip: To add or subtract fractions they need the same denominator. Cross-multiply (a·d ± c·b over b·d), then divide the top and bottom by their greatest common divisor to simplify.
Worked fraction examples
Adding
1/2 + 1/3
= (1×3 + 1×2) / (2×3)
= 5/6
Subtracting
1/2 − 1/3
= (1×3 − 1×2) / (2×3)
= 1/6
Multiplying
1/2 × 1/3
= (1×1) / (2×3)
= 1/6
Dividing
1/2 ÷ 1/3
= 1/2 × 3/1
= 3/2 = 1½
How to use this calculator
-
1
Enter your fractions
Type a numerator and denominator into each fraction. Add a whole number on the left for a mixed number such as 1½.
-
2
Choose the operation
Pick +, −, × or ÷ from the round operator buttons between the two fractions.
-
3
Read the answer
The result shows as a simplified fraction, with the mixed number and decimal below it.
-
4
Simplify or convert
Switch tabs to reduce a single fraction to lowest terms or turn a decimal into a fraction.
Frequently Asked Questions
How do I add two fractions?
Give both fractions the same denominator, add the numerators, then simplify. Using cross-multiplication, a/b + c/d = (a·d + c·b) / (b·d). For example, 1/2 + 1/3 = (3 + 2) / 6 = 5/6.
How do I multiply and divide fractions?
To multiply, multiply the numerators together and the denominators together: 2/3 × 3/4 = 6/12 = 1/2. To divide, flip the second fraction and multiply: 1/2 ÷ 1/4 = 1/2 × 4/1 = 4/2 = 2.
How do I simplify a fraction?
Divide the numerator and denominator by their greatest common divisor (GCD). For example, 8/12 has a GCD of 4, so 8/12 = 2/3. This calculator simplifies every result automatically.
What is a mixed number and how do I enter one?
A mixed number combines a whole number and a fraction, like 1½. Type the whole number in the small box on the left and the fraction beside it. Internally it becomes an improper fraction (1½ = 3/2) for the calculation.
How do I convert a decimal to a fraction?
Write the decimal over a power of ten, then simplify. 0.75 = 75/100 = 3/4. Use the "Decimal → Fraction" tab and the calculator does it for you, reducing to lowest terms.
Is this fraction calculator free and does it work on mobile?
Yes. It's 100% free, needs no sign-up and no download. It works in any modern browser and is fully responsive, so it fits phones, tablets and desktops. Your numbers stay in your browser; nothing is stored or shared.